The present invention relates to a process for producing a double dispensing device like an aerosol device and a container therefor, and more particularly, to a process for producing a double dispensing device characterized in steps of loading stock solution or concentrate and pressurized gas, and to a double dispensing container adapted to the process.
Generally, as known dispensing devices, there are two types of devices, that is, a general type in which stock solution is loaded into a container together with propellant, and a so called xe2x80x9cdouble dispensing devicexe2x80x9d in which stock solution is loaded into a container, and the stock solution is separated from the propellant by means of a barrier wall such as a piston or an inner bag such that the stock solution is pressurized by the propellant through the barrier wall. The latter is used for loading liquid food or the like which is not preferable to be blended with propellant, or stock solution which might react with propellant when they are blended with each other. As the barrier, a collapsible inner bag or a piston that is movable up and down in the container is used generally. In some devices in which a piston is used as a barrier wall, the upper chamber is loaded with stock solution, and the lower chamber is loaded with propellant (liquefied gas or compressed gas). In another case, the upper chamber is loaded with a pressurized gas and the lower chamber is loaded with a stock solution. The latter case is reasonable, since the pressurized gas is low in specific gravity. However, such type of device needs a tube extending bellow from a dispensing valve (aerosol valve) through the piston. In this case, the piston moves by sliding along the tube and an inner wall of the container.
Further, when a stock solution and propellant are loaded into a container, stock solution which can be loaded under atmospheric pressure is loaded fore in a general case, and pressurized gas is thereafter loaded through a gas-loading-valve or by so-called under-cup-loading. The gas-loading-valve might be provided in a bottom of the container or a mounting cup of the dispensing valve. However, the gas-loading-valve attached separately provides excess cost, and the loading process is troublesome. For example, the above-mentioned passing through the piston is produced by the following steps. That is to say, a pipe-like nozzle is inserted through a tube-inserting hole of a piston, and a stock solution is loaded below the piston thereby lifting the piston by means of pressure or buoyancy. Then, under an unstable state that the piston lifts on the way, a tube fixed to the dispensing valve is inserted through the tube-inserting hole of the piston. Then, a pressurized gas is loaded with under-cup-loading through a gap between the dispensing valve and an opening of the container, and immediately after the gas-loading, the dispensing valve is crimped, or the pressurized gas is loaded through a gas-loading-valve separately provided on the container. Therefore, some gap is required between the tube-inserting hole and the tube, and the propellant might leak through the gap.
Therefore, in such type of dispensing device that propellant is loaded in the lower side of the piston, a gas-loading-valve is necessary to be provided in the bottom of the container. Therefore, high cost is required, the loading work is troublesome, and production efficiency is low. In addition, there is probability of leak through the propellant-loading-valve.
In a case of double dispensing device using an inner bag, the loading process is troublesome when under-cup-loading is employed. Specifically, when a loading valve is attached at a bottom of container, cost is high, and there is probability of leak of propellant.
Further, when compressed gas is employed as propellant, the gas-leak problem among the above-mentioned problems becomes important especially, since the loaded amount of the pressurized gas depends on the volume and the upper bound of pressure, and the propellant cannot be loaded in excess. That is to say, when compressed gas is used, the device is very sensitive to leak of gas not similar to the case of liquefied gas.
The object of the present invention is to provide a process for producing a double dispensing device which is easily loaded and propellant does not easily leak. Another object of the present invention is to provide a double dispensing container to be used go for the process.
According to the present invention, there is provided a process for producing a double dispensing device, by providing a pressure-transmittable barrier wall to separate an inside of a vessel (or body of container) into a first chamber and a second chamber, a dispensing valve, a passage to connect the dispensing valve with the first chamber, and a check valve means capable of flowing liquid from the first chamber to the second chamber in a pressure vessel; loading pressurized gas substantially insoluble to stock solution into the first chamber from the valve through the passage, and further bringing the pressurized gas to the second chamber through the check valve means; and loading stock solution into the first chamber through the passage from the valve.
At the step of loading a stock solution from the valve, the gas remaining in the first chamber might be forcibly brought to the second chamber by means of a stock solution loaded into the first chamber. The gas remaining in the first chamber might also be discharged through the valve after the step of loading the gas and before the first chamber is loaded with the stock solution. In the step of loading stock solution in the first chamber, it is preferable to load the stock solution so sufficiently that some stock solution overflow the first chamber to the second chamber.
The double dispensing container of the present invention comprises a pressure vessel; a dispensing valve mounted on a top opening of the vessel; a pressure-transmittable barrier wall for separating an inside of the vessel with airtight manner into a first chamber to be loaded with stock solution and a second chamber to be loaded with pressurized gas; a passage for connecting the valve with the first chamber; and a check valve means for enabling movement of gas from first chamber to the second chamber when pressure in the first chamber is higher than that of the second chamber and for preventing movement of gas from the second chamber to the first chamber when pressure in the second chamber is higher than that of the first chamber. However, it is not necessary to seal perfectly the movement in the reverse direction.
The above-mentioned barrier wall might be a piston which separates the inside of the vessel and is slidable in an up-down direction. The piston might be constructed so as to function as the check valve means for enabling gas movement from the first chamber to the second chamber and for preventing reverse movement. In this case, when the lower side is the first chamber, the above-mentioned passage might be a tube for connecting the valve with the first chamber. When the upper side is the first chamber, the valve might be directly connected with the first chamber.
When the piston functions as a check valve means, it is preferable that the periphery of the piston is yieldable elastically toward inside so that the piston can function as a check valve. Further, a stopper is preferably interposed between the vessel or valve and the piston so as to secure some space for the second chamber with a predetermined volume when the piston moves to decrease the volume of the second chamber. The above-mentioned predetermined volume is preferably 30 to 50% of the volume of the vessel. The stopper can be obtained by an inner face of the vessel or a lower face of the valve to be abutted against the piston.
The above-mentioned barrier wall can be made of a collapsible or deformable inner bag of which inside becomes the first chamber. In this case, the inner bag is preferably provided with a check valve at the bottom of the inner bag or the top of the inner bag or at position near the dispensing valve.
Further, the above-mentioned double dispensing container is preferably provided with a means for forcibly connecting the second chamber with the valve or the first chamber when the barrier wall moves or is deformed to reduce the volume of the first chamber. As the forcibly connecting means for the piston-type-device, a through hole in the tube capable of connecting the inside of the tube with the second chamber, or an element capable deforming or piercing the piston, when the piston moves to reduce the volume of the first chamber, can be employed. As a case of the inner-bag-type, an element to pierce the inner bag to connecting the outer side of the inner bag with the inside of the inner bag or the valve, when the inner bag shrinks, can be employed.
In the case of the above-mentioned piston-type double dispensing container with a tube, a dispensing device can be produced by loading a pressurized gas substantially insoluble to a stock solution into the first chamber from the valve through the tube, and loading a stock solution in the first chamber from the valve through the tube with keeping the container in a right-standing posture to provide motion of the pressurized gas in the first chamber to the second chamber.
In a case of piston-type double dispensing container without a tube, a dispensing device can be produced by loading a pressurized gas substantially insoluble to a stock solution into the first chamber from the valve; and loading a stock solution in the first chamber from the valve with keeping the container in an inverted posture to provide motion of the pressurized gas remaining in the first chamber to the second chamber.
In a case of the inner-bag-type double dispensing container with a check valve at a bottom or top portion, a double dispensing device can be produced by loading a pressurized gas substantially insoluble to stock solution from a valve; and loading a stock solution into the first chamber from the valve with keeping the container in a right standing or inverted posture to provide motion of the pressurized gas remaining in the first chamber toward the second chamber.
In any case of double dispensing containers mentioned above, the pressurized gas in the first chamber might be discharged once after the pressurized gas is loaded, and the stock solution therefore might be loaded into the first chamber.
In the process for producing a double dispensing device of the present invention, not similarly to conventional process, pressurized gas is loaded at first, and stock solution is loaded thereafter. That is to say, when the pressurized gas is loaded into the first chamber from a valve through a passage, such as a tube, at first, the first chamber is filled with the pressurized gas with moving or deforming a barrier wall. Then, the pressurized gas in the first chamber moves to the second chamber through the check valve means. At this situation the pressure in the first chamber is the same as the second chamber. Next, as loading a stock solution into the first chamber from the same valve, the first chamber is filled with the stock solution. During the loading of the stock solution, the pressurized gas do not leak from the second chamber to the first chamber due to the function of the check valve means.
In the process of the present invention, contents can be loaded after the dispensing container has been assembled entirely without employing under-cup-loading. Further, since pressurized gas and stock solution can be loaded from the same valve, any additional gas-loading-valve is not necessary at a bottom of the vessel or the like. Further, loading process is easy, and production efficiency is high. Further, after the loading process, the stock solution in the first chamber is interposed between the pressurized gas in the second chamber and the valve. Therefore, the pressurized gas is in a liquid-sealed condition, and the gas is hard to leak. Therefore, it is convenient to use a compressed gas which is sensitive to leak as propellant.
Beside, at a situation that only pressurized gas is loaded, that is, before the stock solution is loaded, it can be easily confirmed whether there is leak or not.
Among the above-mentioned producing processes, when the process in which the pressurized gas remains in the first chamber and is moved to the second chamber as loading stock solution into the first chamber, is employed, the initial loading pressure of the pressurized gas might be low, and gas-discharging step is not necessary.
In contrast with the above-mentioned, the process in which stock solution is loaded after the pressurized gas in the first chamber is discharged through the valve, has an advantage that the container is not required to stand reversely even if the first chamber is upper side of the vessel. Further, when the pressurized gas is discharged from the first chamber, the pressurized gas is hard to leak from the second chamber to the first chamber by virtue of the function of check valve means.
In the piston-type double dispensing container of the present invention, the pressurized gas can smoothly move from the first chamber to the second chamber since a piston functions as a check valve. Therefore, by loading stock solution into the first chamber with keeping the container in a right stand posture, in which the first chamber to be loaded with stock solution is lower side, or in an inverted posture, only the pressurized gas can be easily loaded into the second chamber through the piston capable of functioning as a check valve. The dispensing container having a stopper for securing a predetermined space at end of stroke of the piston has advantage that the pressurized gas can securely move to the second chamber.
In the inner-bag-type double dispensing device of the present invention, by loading stock solution with the container standing in right or inverted posture in dependent to the position of the check valve, only the pressurized gas can be easily moved to the second chamber through the check valve. Further, in the double dispensing container with means for forcibly connecting, the second chamber is connected with the first chamber or the dispensing valve when the stock solution is used up. Therefore, the pressurized gas remaining in the second chamber can be exhausted outward through the first chamber and the dispensing valve. Therefore, the interior pressure can be reduced before the container is abandoned, and the container can be safely abandoned.